You need to make your method static so it doesn’t require and instance of your Revisions class. The unexpected node is there becuase every class in C has a constructor, hence you see it in the library (Create nodes = constructors). To prevent this, declare your own default constructor and set its access level to private; this will prevent it from importing (and therefore appearing in the library as a node).
All of the above is explained in the document I linked here, plus it will resolve your other issues too: